This is a phase III multicenter, randomized, double-blind, placebo-controlled, parallel-group study to evaluate the efficacy and safety of GSK573719/GW642444 Inhalation Powder, GSK573719 Inhalation Powder, GW642444 Inhalation Powder and Placebo when administered once-daily via a Novel Dry Powder Inhaler over a 24-week treatment period in subjects with COPD. Subjects who meet eligibility criteria at Screening (Visit 1) will complete a 7 to14 day run-in period followed by a randomization visit (Visit 2) then a 24-week treatment period. There will be a total of 9 clinic study visits. A follow-up phone contact for adverse event assessment will be conducted approximately one week after the last study visit (Visit 9 or Early Withdrawal). The total duration of subject participation in the study will be approximately 27 weeks. A subset of subjects at selected sites will also perform 24-hour serial spirometry and Holter monitoring during the study and provide serial blood samples for pharmacokinetic analysis. Sparse pharmacokinetic sampling for population pharmacokinetic analyses will be obtained from non-subset subjects. The primary measure of efficacy is clinic visit trough (pre-bronchodilator and pre-dose) FEV1 on Treatment Day 169. Safety will be assessed by adverse events, 12-lead ECGs, vital signs, clinical laboratory tests, and 24 hour Holter monitoring (subset only).